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Bile stones represent a highly prevalent condition and abnormalities of the biliary tree predispose to stone recurrence due to development of biliary stasis. In our study, we assessed the importance of an altered bile duct course for stone formation.

Biliary atresia is a rare disease of infancy, with an estimated 1 in 15,000 frequency in the southeast United States, but more common in East Asian countries, with a reported frequency of 1 in 5,000 in Taiwan. Although much is known about the management of biliary atresia, its pathogenesis is still elusive. The sea lamprey (Petromyzon marinus) provides a unique opportunity to examine the mechanism and progression of biliary degeneration. Sea lamprey develop through three distinct life stages: larval, parasitic, and adult. During the transition from larvae to parasitic juvenile, sea lamprey undergo metamorphosis with dramatic reorganization and remodeling in external morphology and internal organs. In the liver, the entire biliary system is lost, including the gall bladder and the biliary tree. A newly-developed method called “CLARITY” was modified to clarify the entire liver and the junction with the intestine in metamorphic sea lamprey. The process of biliary degeneration was visualized and discerned during sea lamprey metamorphosis by using laser scanning confocal microscopy. This method provides a powerful tool to study biliary atresia in a unique animal model.

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Isolation of Neonatal Extrahepatic Cholangiocytes

Authors: Sara Karjoo, Rebecca G. Wells.

Institutions: The Children's Hospital of Philadelphia, The Perelman School of Medicine at the University of Pennsylvania.

The intra and extrahepatic bile ducts of the liver are developmentally distinct, and may be differentially affected by certain diseases. However, differences between intra and extrahepatic cholangiocytes, and between neonatal and adult cells, are not well understood.
Methods for the isolation of cholangiocytes from intrahepatic bile ducts are well established1-4. Isolation of extrahepatic ductal cells, especially from the neonate, has not yet been described, although this would be of great benefit in understanding the differences between distinct cholangiocyte populations and in studying diseases such as biliary atresia that appear to target the extrahepatic ducts. Described here is an optimized technique to isolate both neonatal and adult mouse extrahepatic bile duct cells. This technique yields a pure cell population with minimal contamination from mesenchymal cells like fibroblasts.
This method is based on the removal of the extrahepatic ducts and gallbladder, followed by meticulous dissection and scraping to remove fat and fibroblast layers. Structures are embedded in thick layers of collagen and cultured for approximately 3 weeks to allow outgrowth of cholangiocytes in monolayers, which can then be trypsinized and re plated for experimental use.

In acute hepatic failure auxiliary liver transplantation is an interesting alternative approach. The aim is to provide a temporary support until the failing native liver has regenerated.1-3 The APOLT-method, the orthotopic implantation of auxiliary segments- averts most of the technical problems. However this method necessitates extensive resections of both the native liver and the graft.4 In 1998, Erhard developed the heterotopic auxiliary liver transplantation (HALT) utilizing portal vein arterialization (PVA) (Figure 1). This technique showed promising initial clinical results.5-6 We developed a HALT-technique with flow-regulated PVA in the rat to examine the influence of flow-regulated PVA on graft morphology and function (Figure 2).
A liver graft reduced to 30 % of its original size, was heterotopically implanted in the right renal region of the recipient after explantation of the right kidney. The infra-hepatic caval vein of the graft was anastomosed with the infrahepatic caval vein of the recipient. The arterialization of the donor’s portal vein was carried out via the recipient’s right renal artery with the stent technique. The blood-flow regulation of the arterialized portal vein was achieved with the use of a stent with an internal diameter of 0.3 mm. The celiac trunk of the graft was end-to-side anastomosed with the recipient’s aorta and the bile duct was implanted into the duodenum. A subtotal resection of the native liver was performed to induce acute hepatic failure. 7
In this manner 112 transplantations were performed. The perioperative survival rate was 90% and the 6-week survival rate was 80%. Six weeks after operation, the native liver regenerated, showing an increase in weight from 2.3±0.8 g to 9.8±1 g. At this time, the graft’s weight decreased from 3.3±0.8 g to 2.3±0.8 g.
We were able to obtain promising long-term results in terms of graft morphology and function. HALT with flow-regulated PVA reliably bridges acute hepatic failure until the native liver regenerates.

Orthotopic liver transplantation (OLT) in rats using a whole or partial graft is an indispensable experimental model for transplantation research, such as studies on graft preservation and ischemia-reperfusion injury 1,2, immunological responses 3,4, hemodynamics 5,6, and small-for-size syndrome 7. The rat OLT is among the most difficult animal models in experimental surgery and demands advanced microsurgical skills that take a long time to learn. Consequently, the use of this model has been limited. Since the reliability and reproducibility of results are key components of the experiments in which such complex animal models are used, it is essential for surgeons who are involved in rat OLT to be trained in well-standardized and sophisticated procedures for this model.
While various techniques and modifications of OLT in rats have been reported 8 since the first model was described by Lee et al.9 in 1973, the elimination of the hepatic arterial reconstruction 10 and the introduction of the cuff anastomosis technique by Kamada et al.11 were a major advancement in this model, because they simplified the reconstruction procedures to a great degree. In the model by Kamada et al., the hepatic rearterialization was also eliminated. Since rats could survive without hepatic arterial flow after liver transplantation, there was considerable controversy over the value of hepatic arterialization. However, the physiological superiority of the arterialized model has been increasingly acknowledged, especially in terms of preserving the bile duct system 8,12 and the liver integrity 8,13,14.
In this article, we present detailed surgical procedures for a rat model of OLT with hepatic arterial reconstruction using a 50% partial graft after ex vivo liver resection. The reconstruction procedures for each vessel and the bile duct are performed by the following methods: a 7-0 polypropylene continuous suture for the supra- and infrahepatic vena cava; a cuff technique for the portal vein; and a stent technique for the hepatic artery and the bile duct.

In organs, the correct architecture of vascular and ductal structures is indispensable for proper physiological function, and the formation and maintenance of these structures is a highly regulated process. The analysis of these complex, 3-dimensional structures has greatly depended on either 2-dimensional examination in section or on dye injection studies. These techniques, however, are not able to provide a complete and quantifiable representation of the ductal or vascular structures they are intended to elucidate. Alternatively, the nature of 3-dimensional plastic resin casts generates a permanent snapshot of the system and is a novel and widely useful technique for visualizing and quantifying 3-dimensional structures and networks.
A crucial advantage of the resin casting system is the ability to determine the intact and connected, or communicating, structure of a blood vessel or duct. The structure of vascular and ductal networks are crucial for organ function, and this technique has the potential to aid study of vascular and ductal networks in several ways. Resin casting may be used to analyze normal morphology and functional architecture of a luminal structure, identify developmental morphogenetic changes, and uncover morphological differences in tissue architecture between normal and disease states. Previous work has utilized resin casting to study, for example, architectural and functional defects within the mouse intrahepatic bile duct system that were not reflected in 2-dimensional analysis of the structure1,2, alterations in brain vasculature of a Alzheimer's disease mouse model3, portal vein abnormalities in portal hypertensive and cirrhotic mice4, developmental steps in rat lymphatic maturation between immature and adult lungs5, immediate microvascular changes in the rat liver, pancreas, and kidney in response in to chemical injury6.
Here we present a method of generating a 3-dimensional resin cast of a mouse vascular or ductal network, focusing specifically on the portal vein and intrahepatic bile duct. These casts can be visualized by clearing or macerating the tissue and can then be analyzed. This technique can be applied to virtually any vascular or ductal system and would be directly applicable to any study inquiring into the development, function, maintenance, or injury of a 3-dimensional ductal or vascular structure.

Institutions: University of Geneva Hospitals, University of Pavia , University of Geneva, University of Geneva Hospitals.

Clinical progress in the field of liver transplantation has been largely supported by animal models1,2. Since the publication of the first orthotopic rat liver transplantation in 1979 by Kamada et al.3, this model has remained the gold standard despite various proposed alternative techniques4. Nevertheless, its broader use is limited by its steep learning curve5.
In this video paper, we show a simple and easy-to-establish revision of Kamada's two-cuff technique. The suprahepatic vena cava anastomosis is performed manually with a running suture, and the vena porta and infrahepatic vena cava anastomoses are performed utilizing a quick-linker cuff system6. Manufacturing the quick-linker kit is shown in a separate video paper.

Institutions: Indiana University School of Medicine, VITACYTE, LLC, Indiana University School of Medicine, Indiana University School of Medicine.

The interrogation of beta cell gene expression and function in vitro has squarely shifted over the years from the study of rodent tumorigenic cell lines to the study of isolated rodent islets. Primary islets offer the distinct advantage that they more faithfully reflect the biology of intracellular signaling pathways and secretory responses. Whereas the method of islet isolation using tissue dissociating enzyme (TDE) preparations has been well established in many laboratories1-4, variations in the consistency of islet yield and quality from any given rodent strain limit the extent and feasibility of primary islet studies. These variations often occur as a result of the crude partially purified TDEs used in the islet isolation procedure; TDEs frequently exhibit lot-to-lot variations in activity and often require adjustments to the dose of enzyme used. A small number of reports have used purified TDEs for rodent cell isolations5, 6, but the practice is not widespread despite the routine use and advantages of purified TDEs for human islet isolations. In collaboration with VitaCyte, LLC (Indianapolis, IN), we developed a modified mouse islet isolation protocol based on that described by Gotoh7, 8, in which the TDEs are perfused directly into the pancreatic duct of mice, followed by crude tissue fractionation through a Histopaque gradient9, and isolation of purified islets. A significant difference in our protocol is the use of purified collagenase (CIzyme MA) and neutral protease (CIzyme BP) combination. The collagenase was characterized by the use of a6 fluorescence collagen degrading activity (CDA) assay that utilized fluorescently labeled soluble calf skin fibrils as substrate6. This substrate is more predictive of the kinetics of collagen degradation in the tissue matrix because it relies on native collagen as the substrate. The protease was characterized with a sensitive fluorescent kinetic assay10. Utilizing these improved assays along with more traditional biochemical analysis enable the TDE to be manufactured more consistently, leading to improved performance consistency between lots. The protocol described in here was optimized for maximal islet yield and optimal islet morphology using C57BL/6 mice. During the development of this protocol, several combinations of collagenase and neutral proteases were evaluated at different concentrations, and the final ratio of collagenase:neutral protease of 35:10 represents enzyme performance comparable to Sigma Type XI. Because significant variability in average islet yields from different strains of rats and mice have been reported, additional modifications of the TDE composition should be made to improve the yield and quality of islets recovered from different species and strains.

Institutions: The Children's Hospital of Philadelphia, University of Pennsylvania .

Liver fibrosis is defined by the excessive deposition of extracellular matrix by activated myofibroblasts. There are multiple precursors of hepatic myofibroblasts, including hepatic stellate cells, portal fibroblasts and bone marrow derived fibroblasts 1. Hepatic stellate cells have been the best studied, but portal fibroblasts are increasingly recognized as important contributors to the myofibroblast pool, particularly in biliary fibrosis 2. Portal fibroblasts undergo proliferation in response to biliary epithelial injury, potentially playing a key role in the early stages of biliary scarring 3-5. A method of isolating portal fibroblasts would allow in vitro study of this cell population and lead to greater understanding of the role portal fibroblasts play in biliary fibrosis.
Portal fibroblasts have been isolated using various techniques including outgrowth 6, 7 and liver perfusion with enzymatic digestion followed by size selection 8. The advantage of the digestion and size selection technique compared to the outgrowth technique is that cells can be studied without the necessity of passage in culture. Here, we describe a modified version of the original technique described by Kruglov and Dranoff 8 for isolation of portal fibroblasts from rat liver that results in a relatively pure population of primary cells.

Institutions: University of Wisconsin-Madison, University of Wisconsin-Madison, University of Waterloo.

Uncontrolled glycemia is a hallmark of diabetes mellitus and promotes morbidities like neuropathy, nephropathy, and retinopathy. With the increasing prevalence of diabetes, both immune-mediated type 1 and obesity-linked type 2, studies aimed at delineating diabetes pathophysiology and therapeutic mechanisms are of critical importance. The β-cells of the pancreatic islets of Langerhans are responsible for appropriately secreting insulin in response to elevated blood glucose concentrations. In addition to glucose and other nutrients, the β-cells are also stimulated by specific hormones, termed incretins, which are secreted from the gut in response to a meal and act on β-cell receptors that increase the production of intracellular cyclic adenosine monophosphate (cAMP). Decreased β-cell function, mass, and incretin responsiveness are well-understood to contribute to the pathophysiology of type 2 diabetes, and are also being increasingly linked with type 1 diabetes. The present mouse islet isolation and cAMP determination protocol can be a tool to help delineate mechanisms promoting disease progression and therapeutic interventions, particularly those that are mediated by the incretin receptors or related receptors that act through modulation of intracellular cAMP production. While only cAMP measurements will be described, the described islet isolation protocol creates a clean preparation that also allows for many other downstream applications, including glucose stimulated insulin secretion, [3H]-thymidine incorporation, protein abundance, and mRNA expression.

A Method for Murine Islet Isolation and Subcapsular Kidney Transplantation

Authors: Erik J. Zmuda, Catherine A. Powell, Tsonwin Hai.

Institutions: The Ohio State University, The Ohio State University, The Ohio State University.

Since the early pioneering work of Ballinger and Reckard demonstrating that transplantation of islets of Langerhans into diabetic rodents could normalize their blood glucose levels, islet transplantation has been proposed to be a potential treatment for type 1 diabetes 1,2. More recently, advances in human islet transplantation have further strengthened this view 1,3. However, two major limitations prevent islet transplantation from being a widespread clinical reality: (a) the requirement for large numbers of islets per patient, which severely reduces the number of potential recipients, and (b) the need for heavy immunosuppression, which significantly affects the pediatric population of patients due to their vulnerability to long-term immunosuppression. Strategies that can overcome these limitations have the potential to enhance the therapeutic utility of islet transplantation.
Islet transplantation under the mouse kidney capsule is a widely accepted model to investigate various strategies to improve islet transplantation. This experiment requires the isolation of high quality islets and implantation of islets to the diabetic recipients. Both procedures require surgical steps that can be better demonstrated by video than by text. Here, we document the detailed steps for these procedures by both video and written protocol. We also briefly discuss different transplantation models: syngeneic, allogeneic, syngeneic autoimmune, and allogeneic autoimmune.

Institutions: Toronto General Hospital, Toronto General Hospital, Toronto General Hospital.

The success of liver transplantation has resulted in a dramatic organ shortage. In most transplant regions 20-30% of patients on the waiting list for liver transplantation die without receiving an organ transplant or are delisted for disease progression. One strategy to increase the donor pool is the utilization of marginal grafts, such as fatty livers, grafts from older donors, or donation after cardiac death (DCD). The current preservation technique of cold static storage is only poorly tolerated by marginal livers resulting in significant organ damage. In addition, cold static organ storage does not allow graft assessment or repair prior to transplantation.
These shortcomings of cold static preservation have triggered an interest in warm perfused organ preservation to reduce cold ischemic injury, assess liver grafts during preservation, and explore the opportunity to repair marginal livers prior to transplantation. The optimal pressure and flow conditions, perfusion temperature, composition of the perfusion solution and the need for an oxygen carrier has been controversial in the past.
In spite of promising results in several animal studies, the complexity and the costs have prevented a broader clinical application so far. Recently, with enhanced technology and a better understanding of liver physiology during ex vivo perfusion the outcome of warm liver perfusion has improved and consistently good results can be achieved.
This paper will provide information about liver retrieval, storage techniques, and isolated liver perfusion in pigs. We will illustrate a) the requirements to ensure sufficient oxygen supply to the organ, b) technical considerations about the perfusion machine and the perfusion solution, and c) biochemical aspects of isolated organs.

Medicine, Issue 90, ex vivo liver perfusion, marginal grafts, DCD

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Analysis of Nephron Composition and Function in the Adult Zebrafish Kidney

The zebrafish model has emerged as a relevant system to study kidney development, regeneration and disease. Both the embryonic and adult zebrafish kidneys are composed of functional units known as nephrons, which are highly conserved with other vertebrates, including mammals. Research in zebrafish has recently demonstrated that two distinctive phenomena transpire after adult nephrons incur damage: first, there is robust regeneration within existing nephrons that replaces the destroyed tubule epithelial cells; second, entirely new nephrons are produced from renal progenitors in a process known as neonephrogenesis. In contrast, humans and other mammals seem to have only a limited ability for nephron epithelial regeneration. To date, the mechanisms responsible for these kidney regeneration phenomena remain poorly understood. Since adult zebrafish kidneys undergo both nephron epithelial regeneration and neonephrogenesis, they provide an outstanding experimental paradigm to study these events. Further, there is a wide range of genetic and pharmacological tools available in the zebrafish model that can be used to delineate the cellular and molecular mechanisms that regulate renal regeneration. One essential aspect of such research is the evaluation of nephron structure and function. This protocol describes a set of labeling techniques that can be used to gauge renal composition and test nephron functionality in the adult zebrafish kidney. Thus, these methods are widely applicable to the future phenotypic characterization of adult zebrafish kidney injury paradigms, which include but are not limited to, nephrotoxicant exposure regimes or genetic methods of targeted cell death such as the nitroreductase mediated cell ablation technique. Further, these methods could be used to study genetic perturbations in adult kidney formation and could also be applied to assess renal status during chronic disease modeling.

Cholestasis is a clinical condition commonly encountered by both surgeons and gastroenterologists. Cholestasis can cause various physiological changes and affect the nutritional status and surgical outcomes. Study of the pathophysiological changes occurring in the liver and other organs is of importance. Various studies have been done in cholestatic rat models.
We used a reversible cholestatic rat model in our recent study looking at the role of methylprednisolone in the ischemia reperfusion injury. Various techniques for creation of a reversible cholestatic model have been described. Creation of a reversible cholestatic rat model can be challenging in view of the smaller size and unique hepatopancreatobiliary anatomy in rats. This video article demonstrates the creation of a reversible cholestatic model.
This model can be used in various studies, such as looking at the changes in nutritional, physiological, pathological, histological and immunological changes in the gastrointestinal tract. This model can also be used to see the effects of cholestasis and various therapeutic interventions on major hepatic surgeries.

Right Hemihepatectomy by Suprahilar Intrahepatic Transection of the Right Hemipedicle using a Vascular Stapler

Authors: Ingmar Königsrainer, Silvio Nadalin, Alfred Königsrainer.

Institutions: Tübingen University Hospital.

Successful hepatic resection requires profound anatomical knowledge and delicate surgical technique. Hemihepatectomies are mostly performed after preparing the extrahepatic hilar structures within the hepatoduodenal ligament, even in benign tumours or liver metastasis.1-5. Regional extrahepatic lymphadenectomy is an oncological standard in hilar cholangiocarcinoma, intrahepatic cholangio-cellular carcinoma and hepatocellular carcinoma, whereas lymph node metastases in the hepatic hilus in patients with liver metastasis are rarely occult. Major disadvantages of these procedures are the complex preparation of the hilus with the risk of injuring contralateral structures and the possibility of bleeding from portal vein side-branches or impaired perfusion of bile ducts. We developed a technique of right hemihepatectomy or resection of the left lateral segments with intrahepatic transection of the pedicle that leaves the hepatoduodenal ligament completely untouched. 6 However, if intraoperative visualization or palpation of the ligament is suspicious for tumor infiltration or lymph node metastasis, the hilus should be explored and a lymphadenectomy performed.

Caroli's disease is defined as a abnormal dilatation of the intra-hepatica bile ducts: Its incidence is extremely low (1 in 1,000,000 population) and in most of the cases the whole liver is interested and liver transplantation is the treatment of choice. In case of dilatation limited to the left or right lobe, liver resection can be performed. For many year the standard approach for liver resection has been a formal laparotomy by means of a large incision of abdomen that is characterized by significant post-operatie morbidity. More recently, minimally invasive, laparoscopic approach has been proposed as possible surgical technique for liver resection both for benign and malignant diseases. The main benefits of the minimally invasive approach is represented by a significant reduction of the surgical trauma that allows a faster recovery a less post-operative complications.
This video shows a case of Caroli s disease occured in a 58 years old male admitted at the gastroenterology department for sudden onset of abdominal pain associated with fever (>38C° ), nausea and shivering. Abdominal ultrasound demonstrated a significant dilatation of intra-hepatic left sited bile ducts with no evidences of gallbladder or common bile duct stones. Such findings were confirmed abdominal high resolution computer tomography.
Laparoscopic left sectoriectomy was planned. Five trocars and 30° optic was used, exploration of the abdominal cavity showed no adhesions or evidences of other diseases.
In order to control blood inflow to the liver, vascular clamp was placed on the hepatic pedicle (Pringle s manouvre), Parenchymal division is carried out with a combined use of 5 mm bipolar forceps and 5 mm ultrasonic dissector. A severely dilated left hepatic duct was isolated and divided using a 45mm endoscopic vascular stapler. Liver dissection was continued up to isolation of the main left portal branch that was then divided with a further cartridge of 45 mm vascular stapler.
At his point the left liver remains attached only by the left hepatic vein: division of the triangular ligament was performed using monopolar hook and the hepatic vein isolated and the divided using vascular stapler.
Haemostatis was refined by application of argon beam coagulation and no bleeding was revealed even after removal of the vascular clamp (total Pringle s time 27 minutes).
Postoperative course was uneventful, minimal elevation of the liver function tests was recorded in post-operative day 1 but returned to normal at discharged on post-operative day 3.

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